全文获取类型
收费全文 | 123322篇 |
免费 | 7070篇 |
国内免费 | 709篇 |
专业分类
耳鼻咽喉 | 1195篇 |
儿科学 | 3840篇 |
妇产科学 | 2862篇 |
基础医学 | 17805篇 |
口腔科学 | 4531篇 |
临床医学 | 11713篇 |
内科学 | 27421篇 |
皮肤病学 | 3015篇 |
神经病学 | 12027篇 |
特种医学 | 2940篇 |
外国民族医学 | 1篇 |
外科学 | 11194篇 |
综合类 | 500篇 |
一般理论 | 57篇 |
预防医学 | 12284篇 |
眼科学 | 1944篇 |
药学 | 8674篇 |
中国医学 | 498篇 |
肿瘤学 | 8600篇 |
出版年
2024年 | 138篇 |
2023年 | 1192篇 |
2022年 | 2436篇 |
2021年 | 4099篇 |
2020年 | 2572篇 |
2019年 | 3550篇 |
2018年 | 4117篇 |
2017年 | 3106篇 |
2016年 | 3567篇 |
2015年 | 4042篇 |
2014年 | 5166篇 |
2013年 | 6794篇 |
2012年 | 10329篇 |
2011年 | 10726篇 |
2010年 | 5752篇 |
2009年 | 4835篇 |
2008年 | 8459篇 |
2007年 | 8438篇 |
2006年 | 7791篇 |
2005年 | 7285篇 |
2004年 | 6603篇 |
2003年 | 5890篇 |
2002年 | 5306篇 |
2001年 | 665篇 |
2000年 | 482篇 |
1999年 | 683篇 |
1998年 | 879篇 |
1997年 | 722篇 |
1996年 | 638篇 |
1995年 | 504篇 |
1994年 | 465篇 |
1993年 | 390篇 |
1992年 | 338篇 |
1991年 | 234篇 |
1990年 | 241篇 |
1989年 | 211篇 |
1988年 | 200篇 |
1987年 | 176篇 |
1986年 | 200篇 |
1985年 | 144篇 |
1984年 | 182篇 |
1983年 | 158篇 |
1982年 | 189篇 |
1981年 | 159篇 |
1980年 | 153篇 |
1979年 | 93篇 |
1978年 | 90篇 |
1977年 | 83篇 |
1976年 | 69篇 |
1974年 | 64篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Henyse G V Silva Rosangela P Tórtora Maria Lucia F Farias 《Gynecological endocrinology》2005,21(3):174-179
To evaluate the impact of pregnancy on bone, we studied bone turnover at the first (T1) and third (T3) trimester of gestation in 58 adolescents and 28 healthy adolescents who had never been pregnant. Total body (TB) and lumbar spine (LS) bone mineral density (BMD) and body composition were evaluated by dual-energy X-ray absorptiometry in all control patients (C) and after parturition in 28 pregnant patients (G). Paired and unpaired t tests, Mann-Whitney and Pearson correlation tests were used. Bone turnover markers were above the reference range for adult women in more than 80% of the adolescents, with no difference between C and G patients at T1. Increase in urinary N-telopeptide crosslinks of type I collagen and serum bone-specific alkaline phosphatase, markers of bone turnover, was seen during pregnancy ( p < 0.0001). Body composition did not differ between groups, but LS BMD, percentage of expected LS BMD, LS Z-score, percentage of expected TB BMD and TB Z-score were lower in G than C patients ( p < 0.05). TB BMD was positively correlated with LS BMD (r2 = 0.52). The inverse correlations between bone markers and LS BMD suggest that the increased bone turnover during pregnancy probably explains the low bone density after parturition. The impact on future peak bone mass must be studied. 相似文献
32.
33.
We found multimolecular antigenic mimicry of arthritogenic autoantigens and peptides from several other “self” or foreign antigens sharing amino acid sequence homologies. Many of these new mimotopes induced arthritis and/or uveitis upon immunization in Lewis rats, indicating a role for multiple antigens in the initiation of a certain autoimmune disease. 相似文献
34.
Frequency of and risk factors for allergy in primary school children: results of a population survey 总被引:1,自引:0,他引:1
Anna Maria Angioni Giovanni Fanciulli Carlo Corchia † 《Paediatric and perinatal epidemiology》1989,3(3):248-255
During May 1986, a survey to assess the frequency of allergic disorders was conducted among primary school children of Alghero, Sardinia, using a structured self-administered questionnaire. The following problems were investigated: allergic conjunctivitis, asthma, wheezing, allergic rhinitis, urticaria and eczema. Of the original 1823 questionnaires distributed, 1961 (92.8%) were completed by parents and returned. Overall, 238 children (14.1%) were reported to have shown at least one episode of one or more of the above and were regarded as 'allergic'. Among the potential risk factors investigated, statistically significant differences (P less than 0.05) between allergic and non-allergic children were only found for history of allergy in at least one parent (odds ratio, OR = 2.2) and exposure to passive smoking (OR = 1.4). 相似文献
35.
Maria G Papandreou Evdokia V Billis Emmanouel M Antonogiannakis Nikos A Papaioannou 《Journal of orthopaedic surgery and research》2009,4(1):2-9
Background
Anterior cruciate ligament (ACL) injury or reconstruction can cause knee impairments and disability. Knee impairments are related to quadriceps performance – accelerated reaction time (ART) – and disability to performance of daily living activities which is assessed by questionnaires such as the Lysholm knee score. The purposes of this study were to investigate the effect of cross exercise, as supplementary rehabilitation to the early phase of ACL reconstruction: a) on quadriceps ART at the angles 45°, 60° and 90° of knee flexion and, b) on the subjective scores of disability in ACL reconstructed patients. 相似文献36.
Marco Antonio Palma Rocio Ortiz Carlos Alvarez-Dardet Maria T. Ruiz 《Social science & medicine (1982)》2009
The possible effect of Government Consumption (a component of Gross Domestic Product (GDP)) on attainment of the hunger Millennium Development Goal (MDG1) was analyzed by evaluating the effect of macroeconomic, social, demographic and policy variables on average undernourished population. Eighty-four developing countries with data available on undernourished population were included in an ecological study. Regression models were applied to explore possible determinants of Undernourished between 1990 and 2004 and consequent achievement of the projected 2004 MDG1. In 2004, 1.4% of the overall undernourished population in the studied countries [70.16 million people] was in excess of the projected level required to meet MDG1. The multiple linear regression showed significant associations between Undernourished and poverty levels, the Gini Index, rural population and Government Consumption. The multiple logistic regression showed significant associations between achievement of projected 2004 MDG1 levels and Government Consumption and the Gini Index. The significant associations between Undernourished and Government Consumption suggest that the effects of GDP components on social conditions call for more thorough research and that policymakers such as governments and international financial institutions need to ensure that changes in distributive and redistributive policies do not negatively affect the possibility of achieving MDG1. 相似文献
37.
38.
Giorgio Ciprandi Mara De Amici Simone Negrini Gianluigi Marseglia Maria Angela Tosca 《International immunopharmacology》2009,9(10):1247-1249
Two new T cell subsets may be involved in allergic rhinitis (AR) pathogenesis: Th17 and T regulatory cells, mainly producing IL-17 and TGF-β respectively. Successful Sublingual Immunotherapy (SLIT) induces relevant immunological changes, thus the aim of this study was to evaluate serum IL-17 and TGF-β levels in AR patients treated with SLIT for 2 years. Patients' blood samples were collected before initiating SLIT (baseline), three months after the end of the first pre-seasonal SLIT course, and at the end of the second pre-seasonal course. IL-17 was detectable only in the most severe allergic patients. SLIT significantly induced an increase in serum TGF-β levels. There was moreover a significant relationship between TGF-β and symptom severity and drug use at the end of the study. Therefore, this study provides clinically relevant evidence that two pre-seasonal SLIT courses may significantly affect serum TGF-β levels. 相似文献
39.
40.
Eser Tüfek?i Thomas E Merrill Maria R Pintado John P Beyer William A Brantley 《American journal of orthodontics and dentofacial orthopedics》2004,125(6):733-739
Teeth with white spot lesions (WSL) might be more prone to enamel loss during bracket debonding. This in vitro study compared enamel loss from teeth with (n = 14) and without (n = 14) WSL after polishing with low-speed finishing burs or disks (Sof-Lex, 3M ESPE, St Paul, Minn). Debonded surfaces were analyzed with a contact stylus profilometer, and digitized data were compared with baseline readings by using AnSur NT software (Regents, University of Minnesota, Minneapolis, Minn). Specimen surfaces were also examined with a scanning electron microscope. Two-way analysis of variance was performed to analyze the data. In teeth without WSL, the volume losses were 0.16 mm(3) for the bur group and 0.10 mm(3) for the disk group; the mean maximum depths were 47.7 microm for the bur group and 54.3 microm for the disk group. In teeth with WSL, the volume losses were 0.06 and 0.17 mm(3), and the mean maximum depths were 35.1 and 48.7 microm for the bur and disk groups, respectively. There were no significant differences in enamel loss between the 2 groups of teeth without WSL (P =.12). However, in teeth with WSL, the burs removed less enamel than the disks (P = 0.006). Scanning electron microscope examination showed that any damage on the enamel surface was usually located in the cervical third of the teeth. On most specimens, even though tooth surfaces appeared resin-free to the naked eye, there were remnants of it. The differences between groups were so small that they might be clinically insignificant. 相似文献